Method of treating pile fabrics



Feb. 7, 1961 w. w. RANKIN EIAL 2,970,362

METHOD OF TREATING PILE FABRICS Filed June 12, 1956 2 Sheets-Sheet 1 Normal Plane of Fabric M 5 Fabric with Pile 5 Paint of greafesf face down def lection Fabric wifh Pile Beater\ face down Flaf bed S'ream Press INVENTORS WILLIAM W. RANKIN HARRY K.TOWNSLEY THEOPHILUS A. FEILD,JR.

A T TORNEY 1961 w. w. RANKIN ETAL 2,970,362

METHOD OF TREATING FILE FABRICS 2 Sheets-Sheet 2 Filed June 12, 1956 INVENTORS WILLIAM W-RANKIN HARRY K. TOWNSLEY THEOPHILUS A. FEILD,JR.

,4 TTORNEV .Un ed S ates 7 METHOD OF TREATING PILE FABRICS William W. Rankin, Harry K. Townsley, and Theophilus A. Feild, Jr., Charleston, W. Va., assignors to Union This invention relates to improvementsyin thermoplastic pile fabrics.

In the manufacture of dyed deep pile fabrics of thermoplastic fibers the usual practice has been to stock dye the fiber in the desired shades and then use the stock dyed fibers to directly prepare the fabric by knitting or weaving. This required selection of the colors well in advance and stocking the dyed fibers; as a result changes in color during the fashion season presented a serious problem. Fiber dyeing rather than piece dyeing has been necessary because of certain fundamental char acteristics of the fiber.

By thermoplastic fibers is meant such products as fibers of polyacrylonitrile, polyvinyl chloride, polyethylene, polyvinylidine chloride, copolymers of acrylonitrile with vinyl chloride, vinyl acetate, vinylidene chloride, and copolymers of diamines with dicarboxylic acids, and the like.

The thermoplasticity of the synthetic fibers with which this invention is concerned is such that when a thermo plastic fiber pile fabric is made and it is then piece dyed under normal and conventional dyeing conditions the pile becomes flattened. This is caused by the fact that the temperature of the dye bath necessary for dyeing the synthetic fibers is sufiiciently high so as to cause softening and deformation of the thermoplastic fibers. Then after cooling these fibers are still in a deformed state and do not show the desired erect pile on the fabric. Various methods have been investigated to reerect the thermoplastic fiber pile of piece dyed thermoplastic fiber pile fabrics but none, to our knowledge, have been successful. Such methods included combing and brushing of the fabric at various temperatures.

The pile fabrics with which we are concerned are those fabrics, knitted or woven, which have a thermoplastic fiber pile embedded in a base fabric. These pile fabrics may have the appearance of velvet, or they may have the appearance of animal furs such as beaver, muskrat or seal; and the thermoplastic fiber pile may have any height normally used in the preparation of such fabrics. The thermoplastic pile may be embedded in a base cloth consisting of a synthetic fiber, or it may be embedded in a base cloth of'a natural fiber such as 'cotton, wool, linen and silk, or mixtures thereof.

The object of this invention is to provide a method whereby thedeformed and flattened thermoplastic fiber pile of a piece dyed pile fabric can be reerected to a substantially straight upright position. This invention can also be used to reerect the pile of thermoplastic fiber pile fabrics whose pile has been deformed or flattened because of some other treament, as for example due to pressing, steaming, or scouring.

Another object of this invention is to provide a method which will permit the production of dyedqdeep pile thermoplastic fiber pile fabrics while employing the normal and conventional piece dyeing techniques.

More specifically this invention concerns the erection at each side at the selvedges.

2,970,362 Patented Feb. 7, 1961 formed, to at least 230 F. in moisture-free air, or to 210 F. in steam, and preferably to 250 F. in moisturefree air, or to 215 F. in steam, but below the fusion point of said thermoplastic fiber, and vibrating or beating the back base of said heated fabric until the flattened pile has returned to an upright position and then cooling the fabric to room temperature to set the thermoplastic fiber pile in its new erect position.

Referring to the drawings:

Fig. 1 diagrammatically shows a side view of an ap paratus used for erecting the pile of thermoplastic pile fabrics. 1

Fig. 2 is an apparatus similar to that shown in Fig. l but shows the use of a fiat bed steam press for heating and softening the thermoplastic pile.

Fig. 3 is a diagrammatic illustration of a modified commercial pin tenter dryer that can be used for the erection of the pile of thermoplastic pile fabrics.

Fig.4 is a section of line 44 of Fig. 3.

The dyeing of the thermoplastic fiber pile fabric is conducted by the normal and conventional techniques such as, for example, is described in U. S. Patent No. 2,394,689, where polyvinylchloride is dyed from an aqueous dyestulf suspension in the presence of a dyeing assistant; U. S. Patent No. 2,543,316, where thermoplastic fabrics are dyed from an aqueous dyebath solution at temperatures above about C. and preferably under a slight pressure; U.S. Patent No. 2,638,403, where nylon fabrics are dyedwith sulfonamideazo dyestuffs from aqueous solution; and U. S. Patent 2,653,074, where polyacrylonitrile fibers are dyed from aqueous solution by means of the cuprous ion technique.

With reference to Fig. l, a thermoplastic fiber pile fabric was dyed as hereinbefore stated resulting in a fiattened pile 6. The dyed fabric Was then mounted with pile face down on the pulleys 2 and clamped to one of said pulleys 2 by means of a clamp 3. To the other end of the fabric was attached a weight 7 exerting a tension of about 0.5 pound per inch of fabric width. The entire assembly was heated in an oven, not here illustrated, to a temperature above the softening point but below the fusion point of the thermoplastic fibers. Immediately after removal of the assembly from the oven, the thermoplastic pile fabric while still hot was beaten on the base side 4 by a multi-paddle longitudinal beater 1 which rotated at an effective rate sufficient to result in pile erection. The fabric was deflected at the point of contact with the blades of the beater 1 at least about 0.1 inch from the normal straight plane. The blades of the beater 1 are about as wide as the width of the pile fabric. The numeral 5 illustrates the erected thermoplastic fibers resulting from beating the heat-softened fibers.

Fig. 2 is a longitudinal section of another form of ap paratus for accomplishing the same object, namely pile erection, as described above with the equipment of Fig. 1. In thiscase however the pile fabric is heated with steam from a flat bed steam press rather than in a dry oven.

The process of this invention lends itself well to continuous commercial applications, such as is encountered in the continuous drying procedures employed by dyehouses. The dyed thermoplastic fibers pile fabric with flattened and deformed pile 6 is removed from the dye bath and after rinsing and squeezing is dried in a dryer as. illustrated in Fig. 3. The wet fabric is conveyed through the pin tenter dryer supported upon a pair of conveyor like belts, or pin rails, which support the fabric Said belts have thereon in an upstanding position pins 8 which serve to hold the selvedge of the pile fabric. The belts are mounted on a series of pulleys 2 and convey the thermoplastic pile fabric through the dryer which is maintained at a temperature sufficiently high so that it both dries the pile fabric and softens the thermoplastic fibers of the pile thereof. During this period the thermoplastic fibers are stitll in a flattened and deformed state 6. As the warm thermoplastic fiber pile fabric exits from the dryer it is beaten on the base side 4 thereof by a beater 1 which is rotating at a sufficient speed so that effective pile erection occurs. During this beating the pile fabric is deflected from a normal straight plane at least about 0.1 inch and is maintained at a longitudinal tension of about one half pound per inch of fabric width; a slight tension across the width of the fabric is also maintained by means of the pin rails. The paddles on the beater 1 in this case should be slightly shorter than the width of the cloth so that they do not come into contact with the pin rails. The pile fabric, with the erected thermoplastic fibers pile 5 is then conveyed by pulleys 10 through a long loop during which it is cooled by a fan 9 to a temperature below the softening point of the thermoplastic fibers in order to set said fibers in their straight, erect position. From this point on the pile fabric can be handled in the usual manner without danger of damaging the appearance thereof. Fig. 4 is a section of line 4-4 in Fig. 3 and il'ustrates the manner in which the pile fabric is supported on the pins 8 of the pin rails as it is conveyed through the dryer.

The temperature at which the beating of the fabric is conducted will vary and depends upon the particular thermoplastic fiber in the pile fabric, and also upon whether the pile fabric has been heated with steam or in a dry oven. The thermoplastic fibers are heated to a temperature above the softening point of the fibers, but they must not be heated to such a temperature that fusion or melting of the thermoplastic fibers occurs. As an illustration of the temperature requirements thermoplastic fiber pile fabrics consisting of poyacrylonitrile fibers, and fibers of a copolymer of vinyl chloride and acrylonitrile were prepared. It was found that pile fabrics of said thermoplastic fibers are best treated at temperatures of at least about 210 F. preferably at least about 215 F., when steam or moist heat is used to heat the pile fabric; and at a temperature of at least about 230 F., preferably at least about 250 F., when the pile fabric is heated in an oven in the absence of moisture. As previously indicated, any temperature above said temperatures may be used so long as the temperature is not so high that either shrinkage r fusion of the thermoplastic fibers occurs. Lower temperatures are permissaable with moist heat since moist heat tends to soften the thermoplastic fibers at temperatures considerably lower than moisture-free heat. Thus two temperature ranges are available for each thermoplastic fiber in which the process of this invention is operable. It is important that after erection of the pile has occurred that the surface thereof is not disturbed in any wayuntil the thermoplastic fibers have been cooled to below the softening point thereof and set in their new erect position.

After heating the pile fabric to the desired temperature range it is vibrated while held under a tension of about one half pound per inch of fabric width. It has been found that vibration while the fabric is held rigidly in a normal flat plane will not cause erection. However, if the heated fabric is made to vibrate and simultaneously undergo a flexing action pile erection will occur. This flexing action can be from about 0.1 to about inches from the normal flat plane, preferably from about 0.25 to about 3 inches, larger deflections may be used if desired but show no advantages. The fabric is vibrated by means of a paddle or a. vibrating machine, and it does not matter which direction the pile is pointing, upwards, 'sidewards or downwards, While it is being vibrated.

The frequency of vibration and the amplitude of pile fabric deflection from the normal plane due to vibration are factors which are related to each other andmust be controlled. Thus the frequency of vibration has been found to be inversely proportional to the amplitude of deflection; the smaller the fabric deflection hte greater is the frequency of vibration required to obtain pile erection and vice versa; and can be from about 200 to about 10,000 vibrations per minute. The vibratory action can be produced by means of a paddle as illustrated or with a vibrating rod.

The time of beating required to obtain satisfactory erection of the thermoplastic fibers in the pile fabric is also inversely proportional to the amplitude of fabric deflection when the temperature is maintained constant. At a temperature of 250 F. and an amplitude of fabric deflection of one half inch from the flat normal plane, the vibration frequency must be at least about 500 beats per minute for a period of about 14 seconds or pile erection will not occur. At a deflection of one inch, at the same temperature, satisfactory pile erection will occur in a period of about 7 seconds at a frequency of about 2,000 vibrations per minute. Thus it can be seen that for each deflection the thermoplastic fiber pile fabric must be vibrated at a certain rate and for a specified time to realize satisfactory pile erection. In every case the fabric must be maintained under sufficient tension so that the back of the pile fabric maintains contact with the beating or vibrating mechanism.

If the construction of the pile fabric is such that it may be damaged by the action of the beater, the pile fabric can be protected by interposing a membrane, for example a piece of cloth, between the beater tend the pile fabric.

The following examples further illustrate this invention. a

7 EXAMPLE 1 A pile fabric consisting of a 0.5 inch pile of fibers ofa thermoplastic copolymer of vinyl chloride and acrylonitrile, commercially marketed as Dyncl, woven on a cotton back was dyed blue in a conventional dyeing manner using an aqueous dyebath. The dyed fabric after drying had a flattened pile. A 9 inch by 30 inch section of this dyed fabric was heated pile down to about 250 F. by a 10 minute exposure in a circulating air oven maintained at this temperature. The fabric was removed from the oven and immediately vibrated under a tension of 0.5 pound per inch of fabric Width using the beating machine illulstrated in Fig. 1. The back of the fabric was subjected to a beating or vibratory action at a beating frequency of about 2,000 beats per minute for a period of 7 seconds. Fabric deflection at the point at which the beating occurred Was about 1 inch from its normal straight plane. After the beating the pile erected fabric was cooled taking care to avoid any contact of the pile with any object which would tend to alter the position of the erected thermoplastic pile fibers. After cooling the thermoplastic pile was completely in an erect position and free of the original irregularities;

Additional examples employing the method and thermoplastic pile fabric of Example 1, and illustrating the effect of changing the variables and of time, frequency and deflection are summarized in Table I.

Table I Beats Beating Fa ric Effective Ex. Temp, per time, dcfiecness of pile F. Minute seconds tin erection inches 250 2.000 3. 5 1. 0 Incomplete. 250 2. 000 14 0. 5 Complete. 250 2. (m0 7 0. 5 Incomplete. 220 2. 000 14 0. 5 Do. 230 2.000 14 '0. 5 Do. 250 4, 000 14 0. 25 Complete. 250 4. 000 7 0.25 Do. 250 4, 000 3. 5 0. 25 Incomplete. 250 1, 000 14 0. 5 Complete. 250 500 14 0. 5 Do. 250 250 14 0. 5 None.

EXAMPLE 13 A 60 inch wide by 5 yards long piece of a pile fabric consisting of a 0.5 inch pile of fibers of a thermoplastic copolymer of vinyl chloride and acrylonitrile, commercially marketed as Dynel, woven on a cotton back was dyed a navy blue shade in a conventional dyeing manner using an aqueous dyebath. The dyed fabricwas cooled slowly to avoid wrinkles and vacuum extracted. At this point the thermoplastic pile of the fabric was completely flattened. The fabric was dried in the pin tenter drier of Fig. 3 at a constant temperature of 240 F. As the fabric emerged from the drier, a four bladed longitudinal beater operating at a speed of about 1725 r.p.m. beat the back of the fabric for a period of about 1 second. Fabric deflection at the point at which beating occurred was estimated to be about 1.5 inches. The pile erected fabric was then cooled to below the distortion point of the thermoplastic fibers by means of the fan 9 (Fig. 3). After this treatment the thermoplastic fibers pile was completely in an erect position and free of the original irregularities.

EXAMPLE 14 A 9 inch by 30 inch piece of the same Dynel pile fabric used in Example 1 and having a flattened pile was installed in the beating apparatus illustrated in Fig. 2 With the pile of the fabric facing down. The fabric was then heated to a temperature of about 215 F. by allowing steam to flow through the bed of the steam press. With the fabric under a tension of about 0.5 pound per inch of fabric width the fabric was then subjected to a beating or vibratory action by means of the beater 1, Fig. 2, for a period of about 14 seconds at a beating frequency of about 1800 beats per minute. The fabric was deflected about 1 inch from its normal straight plane at the point at which contact with the beater occurred. The pile fabric was cooled following the beating, taking'all necessary precautions to avoid any contact of the erected thermoplastic pile with anything which would tend to alter the position of the erected pile fibers. After cooling the pile of the piece dyed fabric was erect and free from the original irregularities.

When this example was repeated using a beating frequency of about 1000 beats per minute at about 215 F. no pile erection resulted. At a temperature of 202 F. and a beating frequency of about 1800 beats per minute pile erection was incomplete.

Table II summarizes the conditions and results'obtained with a pile fabric consisting of a 0.5 inch'pile of fibers of a thermoplastic polyacrylonitrile, commercially marketed as Orion, woven on a cotton back which had been dyed in a conventional manner using an aqueous dyebath. The pile of the dyed fabric was flattened and irregular prior to treatment by the method of this invention.

Table II Beats Beat- Fabric Tem Beating per ing deflee- Efiective- Ex. Apparamintime, tion. ness of pile tus ute secinches erection ends 250 Fig. 1-.- 2,000 7 1.0 Complete. 250 Fig. 1-.- 2,000 3.5 1.0 Incom lete. 250 Fig. 2,000 14 0. 5 Comp etc 250 Fig. 2. 000 7 o. 5 Incomplete 250 Fig. 4, 000 14 0. 25 comlplete 250 Fig. 4, 000 7 0. 25 o. 250 Fig. 1..- 4, 000 3. 5 0. 25 Incomplete. 250 Fig. 1--. 1, 000 14 0. 5 Do. 250 Fig. 500 14 0. 5 None. 215 Fig. 1, 800 14 1.0 Complete. 215 Fig. 2... 1, 000 14 1. 0 None. 202 Fig. 2. 1, 800 14 1. 0 Incomplete.

In Table III are summarized the conditions and results obtained with a pile fabric consisting of a 0.5 inch thermoplastic pile of a blend of 70% Orlon and 30% Dynel woven on a cotton back. This pile fabric had been dyed in a conventional manner using an aqueous dyebath and the pile of the dyed fabric was flattened and irregular after drying. The apparatus of Fig. 1 was used to obtain pile erection.

Table III Beats Beating Fabric Effective- Ex. Temp., per time, defiecness of pile F. minute seconds tion, erection inches 250 2, 000 14 0. 5 Complete. 250 2, 000 7 0. 5 Incomplete. 250 2,000 7 1. 5 Complete. 250 2,000 7 1.0 Do. 250 2, 000. 3. 5 1. 0 Incomplete. 250 4, 000 14 0. 25 Complete. 250 4. 060 7 0. 25 Do. 250 v 4, 000 3. 5 0. 25 Incomplete.

What is claimed is:

1. The method for erecting the pile of fabrics having I resin, which comprises softening said pile fabrics by heating said pile fabric at a temperature of from about 200 F. to about 300 F., beating the back side of said heated fabric perpendicularlythereto at a frequency of from about 250 to about 10,000 beats per minute, the rate of beating being inversely proportional to the temperature, while said fabric is deflected from about 0.1 inch to about 3 inches from a straight line at the point at which the beating occurs, said frequency of beating being inversely proportional to said deflection, while said fabric is maintained at a tension of at least about one half pound per inch of fabric width, for a period of from about 1 to about 30 seconds, and then cooling the pile fabric to a temperature below the softening point of the thermoplastic fibers.

2. The method of claim 1, wherein the pile fabric is heated at from about 220 F. to about 260 F., the frequency of beating is from about 500 to about 5,000 beats per minute, and the deflection is from about 0.25 inch to about 1.5 inches.

3. The method of claim 1, wherein the pile fabric is heated by steam to from about 210 F. to about 225 F., the frequency of beating is from about 1,200 to about 3,000 beats per minute, and the deflection is from about 0.25 inch to about 1.5 inches.

References Cited in the file of this patent UNITED STATES PATENTS 1,889,902 Moore Dec. 6, 1932 2,035,641 Dickie et al. Mar. 31, 1936 2,629,918 Swing Mar. 3, 1953 2,705,880 Kinzinger et'al. Apr. 12, 1955 2,737,702 Schmidt et al. Mar. 13, 1956 2,785,042 Grajeck et al. Mar. 12, 1957 FOREIGN PATENTS 13,868 Great Britain 1887 999,105 7 France Oct. 3, 1951 

